The anti-convulsant carbamazepine (CBZ) has been proposed as a pharmacological treatment for cocaine addiction, but there is little systematic data from controlled human studies on its efficacy or the safety of its interactions with cocaine. This double-blind, double dummy, placebo-controlled (diphenhydramine-25 mg BID) residential study is the largest, most detailed to date investigating the clinical pharmacology of the CBZ-cocaine interaction. Eighteen cocaine-dependent subjects (not currently dependent on other substances) were randomly assigned to 4 parallel groups: (1) low plasma CBZ level (1-3 mg/L), (2) placebo short-stay (6 weeks), (3) medium plasma CBZ level (4-7 mg/L), or (4) placebo long-stay (9 weeks). Subjects could self-administer cocaine-25 mg IV (or blank) or receive a monetary reward up to thrice daily three days each week by making a stimulus-controlled operant response. On self-administration days, subjects underwent 24-hour ambulatory monitoring of cardiovascular function, and answered computer-administered questions on their subjective state. Subjects' response to cocaine-associated stimuli and their EEG and cognitive function were assessed periodically. Thus, the influence of CBZ on cocaine reinforcement and cocaine-induced psychological and physiological effects could be assessed. Blood, saliva, and hair samples were collected periodically to assess cocaine and CBZ pharmacokinetics. Data collection has been completed, and data analysis is beginning.